Conformationally constrained imidazolecarboxylic acid esters hydrolyze by way of their cyclic acylimidazoles. Acylimidazoles have been implicated in a variety of other reactions of these systems, providing evidence that high energy bonds can be created enzymatically solely by the trapping of entropic free energy. Synthesis of the last, but highly elusive, compound in the current series has finally been achieved. As anticipated, this compound shows a high tendency toward utilization of the free energy of water formation as the sole means for generation of high energy bonds. Kinetic studies are in progress to provide a clear model for the Mitchell hypothesis. Fluoro analogs of these compounds are being prepared to study conformational flexibility in aqueous solution.